This case study report describes a grid-interactive efficient building (GEB) renovation project at the General Services Administration's (GSA's) Oklahoma City (OKC) Federal Building, and demonstrates that GEB-ready strategies and technologies can be deployed across buildings with minimal investment. The case study showcases a leading example of a GEB project in the federal buildings space and provides key information on the project roles, processes, costs, and benefits. The findings from this successful GEB project can be used to help pave the way for additional GEB-ready retrofits in the future.